By Lucia Binding, news reporter
Army engineers have received permission to start planning and building 57 miles of 5.5m (18ft) high fencing along the US border with Mexico.
The Pentagon is diverting $1bn (£758m) of funding to support the project, which acting defence secretary Patrick Shanahan says is designed to block "drug-smuggling corridors".
The fencing is going to be erected in Yuma, Arizona and El Paso, Texas – and both areas have recently seen illegal border crossings increase.
Many of those who attempt to cross are asylum-seeking families from Central America.
A statement explained that the funds will also be used for "constructing and improving roads and installing lighting" to support counter-narcotic activities undertaken by federal law enforcement agencies.
Building a border wall to stop criminals from entering the US was a key promise of Donald Trump's presidential campaign in 2016 – but at the time, he had claimed it would be paid for by Mexico, not American taxpayers.
The president caused controversy when he declared that there is a national emergency at the Mexican border.
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A vote designed to try and override this declaration appears certain to fail when it reaches the House of Representatives on Tuesday.
If it does fail, Mr Trump will be able to shift an additional $3.6bn (£2.7bn) from military construction projects to building a barrier along America's southwest boundary.
After the Pentagon's $1bn transfer to commence wall construction in Arizona and Texas, the president's son, Donald Trump Jr, tweeted: "Christmas came early this week."
That message, which was retweeted by the president, may also have been referring Read More – Source